1.1 本试验方法包括通过玻璃比重计结合一系列通常作为液体处理并具有雷德蒸气压的原油和石油产品的API比重计算进行测定（试验方法 第323页 )14.696磅/平方英寸（101.325 kPa）或更小。值在现有温度下确定，并在60 °F（15.56 °C），或转换为60 °F，通过附件 1250美元 通用原油、精炼产品和润滑油（API 英里/分钟 第11.1章）。这些表格不适用于非碳氢化合物或基本上纯的碳氢化合物，如芳烃。 1.2 获得的初始值是未校正的比重计读数，而不是密度测量值。在参考温度或其他合适温度下在比重计上测量值，并通过石油测量表校正弯液面效应、热玻璃膨胀效应、替代校准温度效应和参考温度的读数；在参考温度以外获得的值是比重计读数，而不是密度测量值。 1.3 在进行任何计算之前，应记录测定的初始比重计读数。然后进行第节中要求的计算 9 应在后续计算程序（测量票计算、仪表系数计算或基本校准体积测定）中使用最终结果之前进行并记录。 1.4 以英寸-磅单位表示的值应视为标准值。括号中给出的值是对SI单位的数学转换，仅供参考，不被视为标准值。 1.5 本标准并不旨在解决与其使用相关的所有安全问题（如有）。 本标准的使用者有责任在使用前建立适当的安全、健康和环境实践，并确定监管限制的适用性。 有关特定警告声明，请参阅 8.5 . 1.6 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《国际标准、指南和建议制定原则决定》中确立的国际公认标准化原则制定的。 =====意义和用途====== 5.1 准确测定石油及其产品的比重对于将测量体积转换为标准温度为60℃时的体积是必要的 °F（15。 56 °C）。 5.2 该程序最适用于测定低粘度透明液体的API比重。该试验方法也可用于粘性液体，方法是让液体比重计有足够的时间达到温度平衡，并通过采用适当的弯液面修正来用于不透明液体。此外，对于透明和不透明流体，在校正至参考温度之前，应针对热玻璃膨胀效应校正读数。 5.3 当与散装油测量一起使用时，通过在尽可能接近参考温度的温度下观察比重计读数，可将体积校正误差降至最低。 5.4 重力是控制原油质量的一个因素。然而，石油产品的比重是其质量的不确定指标。与其他财产相关，重力可以用来给出近似的碳氢化合物组成和燃烧热。 5.5 重力是汽车、航空和船用燃料的重要质量指标，它影响储存、搬运和燃烧。

1.1 This test method covers the determination by means of a glass hydrometer in conjunction with a series of calculations of the API gravity of crude petroleum and petroleum products normally handled as liquids and having a Reid vapor pressure (Test Method D323 ) of 14.696 psi (101.325 kPa) or less. Values are determined at existing temperatures and corrected to values at 60 °F (15.56 °C), or converted to values at 60 °F, by means of Adjunct to D1250 Standard Guide for the Use of the Joint API and ASTM Adjunct for Temperature and Pressure Volume Correction Factors for Generalized Crude Oils, Refined Products, and Lubricating Oils (API MPMS Chapter 11.1). These tables are not applicable to nonhydrocarbons or essentially pure hydrocarbons such as the aromatics. 1.2 The initial values obtained are uncorrected hydrometer readings and not density measurements. Values are measured on a hydrometer at either the reference temperature or at another convenient temperature, and readings are corrected for the meniscus effect, the thermal glass expansion effect, alternate calibration temperature effects and to the reference temperature by means of the petroleum measurement tables; values obtained at other than the reference temperature being hydrometer readings and not density measurements. 1.3 The initial hydrometer readings determined shall be recorded before performing any calculations. Then the calculations required in Section 9 shall be performed and documented before using the final result in a subsequent calculation procedure (measurement ticket calculation, meter factor calculation, or base prover volume determination). 1.4 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For specific warning statement, see 8.5 . 1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 5.1 Accurate determination of the gravity of petroleum and its products is necessary for the conversion of measured volumes to volumes at the standard temperature of 60 °F (15.56 °C). 5.2 This procedure is most suitable for determining the API gravity of low viscosity transparent liquids. This test method can also be used for viscous liquids by allowing sufficient time for the hydrometer to reach temperature equilibrium, and for opaque liquids by employing a suitable meniscus correction. Additionally for both transparent and opaque fluids the readings shall be corrected for the thermal glass expansion effect before correcting to the reference temperature. 5.3 When used in connection with bulk oil measurements, volume correction errors are minimized by observing the hydrometer reading at a temperature as close to reference temperature as feasible. 5.4 Gravity is a factor governing the quality of crude oils. However, the gravity of a petroleum product is an uncertain indication of its quality. Correlated with other properties, gravity can be used to give approximate hydrocarbon composition and heat of combustion. 5.5 Gravity is an important quality indicator for automotive, aviation and marine fuels, where it affects storage, handling and combustion.